ocr: Poland faces serious pollution problems from two generations ofheavy industrialization. A third ofPoles live in areas regarded: as extremely polluted. In the southern region of Silesia, air, water and vegetation pollution are especially severe. The metallurgical industry and thermal electric power stations are significant sources ofair pollution. Sulfur dioxide readings in Krakow can exceedlegal limits by 800 times. Only 4% ofPoland's rivers have water consideredfit for human consumption; 75% had been declared biologically dead by the late 1980s. Any clean-up operation wouldbe expensive.
